System and method of in-situ shale oil recovery utilizing an intense down-hole solar beam

ABSTRACT

A system for in-situ oil shale recovery, which includes a well casing having a leak-tight shaft liner, a gas evacuating system for removing gases from the well casing, and a solar collection system for directing a source of radiant energy through the well casing to a strata of oil shale.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 60/941,593, filed Jun. 1, 2007, which is incorporated herein by this reference in its entirety.

FIELD OF THE INVENTION

This application relates to a unique means of in-situ shale oil recovery utilizing an intense down-hole solar beam of radiant energy from the sun, and more particularly to a system and method of in-situ shale oil recovery utilizing an evacuated well casing, which conveys the intense solar beam of radiant energy to a strata of oil shale.

BACKGROUND

It has been estimated that two trillion barrels of crude oil are potentially recoverable from shale oil located in the eastern and western states of the United States. However, unlike oil and natural gas, oil shale is easy to locate using current technology. The Mahogany Research Project®, which is an initiative by the Shell Oil Company®, is designed to procure oil from the geologically-termed “Mahogany” layer of oil shale rock on the Colorado plateau. In accordance with the Mahogany Research Project, sections of the vast oil shale field are heated in situ (where it is) deep underground, releasing the oil and natural gas from the rock so that it can be pumped to the surface and made into fuel.

In the Mahogany Research Project, the oil shale rock is heated to a temperature of approximately 700° F. (371° C.) using heating elements that are embedded into the oil shale rock. The oil and natural gas is then baked out of the rock creating pools that can then be pumped to the surface. Although, this process requires a great deal of energy, it is anticipated that the process will produce more energy than it expends (approximately 3.5 times as much energy comes out as goes in) making it a viable option for the recovery of oil and natural gas.

Accordingly, it would be desirable to utilize an in-situ shale oil recovery system, which utilizes an intense down-hole solar beam of radiant energy from the sun.

SUMMARY

In accordance with one embodiment, a system for in-situ oil shale recovery comprises: a well casing having a leak-tight shaft liner; a gas evacuating system for removing gases from the well casing; and a solar collection system for directing radiant energy through the well casing to a strata of oil shale.

In accordance with another embodiment, a light tube comprises: one or more solar collectors for collecting and directing radiant energy; an evacuated well casing; a liner within the evacuated well casing, the liner having an internal surface treatment to minimize thermal absorption in an upper section of the well casing; one or more transparent, gas tight windows positioned within the well casing; and an absorber surface treatment on a lower section of the well casing, the lower section of the well casing being adjacent to a target rock strata, which produces an in-situ oil recovery by absorbing the radiant energy and effectively transmitting resultant heat to the target rock strata.

In accordance with a further embodiment, a method of in-situ oil shale recovery comprises: evacuating a well casing; lining an upper section of the well casing with an internal surface treatment to minimize thermal absorption; applying a surface treatment on a lower section of the well casing adjacent to a target strata of oil shale, the surface treatment adapted to absorb radiant energy; and producing in-situ oil recovery by transmitting the radiant energy to the target strata of oil shale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a system and method of in-situ oil recovery utilizing a down-hole solar beam in accordance with an exemplary embodiment.

FIG. 2 is a perspective view of a system and method of in-situ oil recovery utilizing a down-hole solar beam in accordance with another exemplary embodiment.

FIG. 3 is a cross-sectional view of a system and method of in-situ oil recovery utilizing a non-imaging optic system in accordance with another exemplary embodiment.

FIG. 4 is a cross-sectional view of a solar collection system in accordance with an exemplary embodiment.

FIG. 5 is a cross-sectional view of a solar collection system in accordance with another exemplary embodiment.

DETAILED DESCRIPTION

In accordance with an exemplary embodiment, the system 100 as shown in FIG. 1, provides a unique means of effectively applying radiant energy from the sun to a strata 110 below the earth's surface containing oil shale 112. The system 100 uses a specially designed light tube comprising a well casing 120 located within a drill hole or drill shaft 102. The well casing 120 includes a sealed and evacuated liner (i.e., a leak-tight liner) 122 positioned within the well casing 120, which avoids thermal convection and unwanted movement of heat toward the upper regions of the well casing 120. In accordance with an exemplary embodiment, the system 100 is configured to heat sections of an oil shale field in situ, releasing the oil and natural gas from the strata so that the oil and natural gas can be pumped to the surface and made into fuel.

In accordance with an exemplary embodiment, the evacuated liner or leak-tight liner 122 acts as a light tube, which utilizes a liner with an optionally included internal surface treatment 126, which minimizes the thermal absorption in the upper section of the drill shaft 102 and conveys (i.e., delivers) a solar heat source or radiant energy to the targeted strata 110 of shale oil 112 within the shaft 102. For example, in the Colorado plateau (i.e., the Mahogany Project), the targeted strata 110 of shale oil 112 is located at approximately one-thousand (1000) feet below a terrain surface 184.

In accordance with an exemplary embodiment, the leak-tight liner 122 utilizes one or more transparent, gas tight windows 130, 134, which are positioned within the inner or interior portion 124 of the leak-tight liner 122. The gas tight windows 130, 134 are preferably made of refractory material, which contains a dispersed refractory material (not shown). The dispersed refractory material absorbs the solar rays and delivers a heat source in the form of radiant energy to the target heating region of the shaft 102 and well casing 120. It can be appreciated that the solar heat source or radiant energy is preferably a concentrated energy in the form of light, light rays, solar energy, or solar flux, which provide the energy to heat the oil shale strata 110 in situ.

In accordance with a further exemplary embodiment, the system 100 can include a solar collection system 150 comprised of one or more solar collectors and/or concentrators, and collimator systems, which collects and conveys (or directs) the resulting radiant energy in the form of intense solar light beam down through the well casing 120, which has been drilled through the overburden soils and extending into the oil shale strata 110. In accordance with an exemplary embodiment, the system 100 acts as a light tube that can withstand high temperatures and has minimal interaction with surrounding rock strata and products of in-situ oil recovery by absorbing radiant energy and effectively transmitting resultant heat to target rock strata.

In accordance with another exemplary embodiment, the system 100 acts as a light tube, which can convert the well casing 120 into a production well once the necessary rock strata temperatures have been reached, and oil and natural gas production can begin.

In accordance with an exemplary embodiment, the system 100 of in-situ oil recovery utilizing a down-hole solar beam of radiant energy enables long term heating of oil shale strata (i.e., an oil bearing formation) 110 by solar energy. In accordance with an exemplary embodiment, the system 100 permits in-situ conversion of oil shale 112 to an oil by-product. It can be appreciated that once the target strata 110 has reached approximately 650° F. to 700° F., the solar assembly or parts thereof (i.e., solar collection system 150) can be moved to another site, and oil pumping can commence either through the existing shaft (i.e., well casing 120) or through nearby separate drill holes.

As shown in FIG. 1, the oil shale strata 110 include an upper edge or boundary 114 and a lower edge or boundary 116 with oil shale 112 therein. In accordance with an embodiment, the oil shale strata 110 can include a surrounding freeze barrier (not shown) to preclude or prevent the subterranean flow of water into the oil shale strata 110.

In an exemplary embodiment, the system 100 includes a well hole or drill shaft 102 having a well casing 120, which includes a leak-tight shaft liner 122, and a gas evacuating system 140 to remove gases from an inner portion or interior 124 of the well casing 120. The system 100 also preferably includes a solar collection system 150 for collecting and directing a collimated light beam 160 of radiant energy through the interior 124 of the shaft liner 122 of the well casing 120 to the targeted oil shale strata 110. The system 100 can also include a flush tube 192 for removal of gases and/or other materials from within the inner or interior portion 124 of the well casing 120.

In accordance with an exemplary embodiment, the leak-tight shaft liner 122 is a leak-tight stainless steel shaft liner of at least 4 inches in diameter, and more preferably of at least 8 inches in diameter having a ¼ inch wall or equivalent with a transparent top window 130, which is configured to convey a collimated solar light beam 160 through the interior portion 124 of the shaft liner 122 to the target oil shale strata 110. The well casing 120 also preferably includes a removable bottom plate or plug 132. The removable bottom plate or plug 132 is preferably located at or below a lower edge or surface 116 of the target shale strata 110. In an exemplary embodiment, the bottom plate or plug 132 is opaque.

In accordance with another exemplary embodiment, the system 100 can include a bottom window 134, which is positioned within the interior 124 of the shaft liner 122 and at or slightly above an upper portion 114 of the oil shale strata 110.

In accordance with an exemplary embodiment, the system 100 includes a gas evacuating system 140, which is configured to remove gases 142 from the inner or interior portion 124 of the shaft or well casing 120. The gas evacuating system 140 preferably includes a pump or other suitable suction device (not shown), which removes any and all gases from within the well casing 120. The removal of any and all gases 142 from the inner or interior portion 124 precludes unwanted thermal convection and other down hole (or well casing 120) losses.

In accordance with an exemplary embodiment, the solar collection system 150 includes at least one adjustable aiming mirror 152, at least one beam collimator 154, and at least one concentrator 156 having a heliostat (not shown).

The at least one concentrator 156 includes a reflective surface which redirects the sunlight and radiant energy from the sun to the collimator 154. In order to maximize the amount of solar energy and heat generated by the system 100, the concentrator 156 preferably is always directly facing the sun throughout each day and throughout each season of the year. Further, the concentrator 156 is also preferably designed to follow the daily path of the sun as the sun travels across the sky and also to allow the concentrator 156 to continually face the sun approximately perpendicularly throughout the year. In accordance with an exemplary embodiment, the concentrator includes a heliostat or other tracking mechanism (not shown) that tracks the movement of the sun.

In accordance with an exemplary embodiment as shown in FIG. 1, the concentrator 156 is oriented such that it collects and directs (i.e. reflects) the sunlight and radiant energy from the sun to the collimator 154, which directs a collimated beam of light 160 to the at least one adjustable aiming mirror 152. The at least one adjustable aiming mirror 152 redirects the collimated beam of light (sunlight) along a fixed axis towards the gas tight window 130 positioned on an upper end of the well casing 120.

In accordance with an exemplary embodiment, the system 100 also includes an adjustable aperture 190, which receives the collimated light beam 160 from the aiming mirror 152 and directs the light beam though the casing 120 to the desired oil shale strata 110. The adjustable aperture 190 can be any suitable hole or opening through which the collimated light beam 160 is admitted.

The at least one beam collimator 154 preferably gathers or collimates the plurality of solar light beams into a single intense narrow beam or collimated solar light beam 160, which is directed by the at least one aiming mirror 152 down the hole or well casing 120. It can be appreciated that the collimator 154 can be any suitable device that narrows a beam of particles or waves, such as a collimator 154 may consist of a curved mirror or lens with some type of light source and/or an image at its focus. The at least one adjustable aiming mirror 152 receives the collimated light beam 160 from the collimator 154 and directs the collimated light beam 160 through or down the well casing 120.

In accordance with an exemplary embodiment, it can be appreciated that by removing all gases from the well casing 120 prior to the collimated beam 160 of radiant energy reaching the targeted oil shale 112, the system 100 can produce, generate and/or maintain sufficient heat within the well casing 120 to achieve a target temperature of approximately 650° F. to 700° F. without unnecessary heat losses through unwanted thermal convection.

In accordance with an exemplary embodiment, the shaft liner 122 can include a reflective inner surface or liner 126, which acts as a light tube within the well casing 120 above the strata 112. In addition, it can be appreciated that by adding a reflective inner surface or liner 126 to the well casing 120, the reflective inner surface or liner 126 can reduce the collimator lens requirements of the system 100.

As shown in FIG. 1, the lower portion of the well casing 120, which is adjacent to the oil shale strata 110 preferably includes a stainless steel fiber liner 144, which absorbs the resultant radiant heat from the light beam 160 received from the aiming mirror 152. The lower portion of the well casing 120 can also include an absorber surface treatment 146, which is configured to absorb the heat from the well casing 120 to bake the oil shale 112. In addition, at least one additional beam shaping lens 194 can be positioned within the inner or interior portion 124 of the well casing 120 to assist with the guidance of the collimated light beam 160 to a desired portion of the well casing 120.

In accordance an exemplary embodiment, the system 100 as described herein, if located on the Colorado plateau could produce incident solar radiation of at least approximately 50 watts per hour (watts/hr) for at least 8 hours per day (hours/day) for at least 200 days per year (days/year), which would produce heating of 80 kilowatt hours per year (kwhr/year).

It can be appreciated that once the oil and natural gas is released from the oil shale strata 110, the oil and natural gas is preferably removed from beneath the terrain surface 184 through an oil production pipe or system 180. The oil production pipe or system 180 preferably includes a valve system 186, which controls the flow and/or removal of the oil and natural gas from the oil shale strata 110.

In accordance with an exemplary embodiment, the concentrator 156 and heliostats (not shown) can be supported on an elevated frame structure 182. The elevated frame structure not only provides support for the concentrator 156 and/or heliostats, but also can be used to improve the light tube and passage of the sunlight and radiant energy to the collimator 154, aiming mirror 152 and well casing 120.

As shown in FIG. 2, in accordance with another exemplary embodiment, the well casing 120 can also includes a heat transport material 125, such as a liquid salt. The heat transport material 125 produces a negative thermal expansion coefficient, such that the heat or radiant energy from the solar light beam 160 is conveyed down-hole by convection. The heat transport material 125 is preferably a liquid salt or other suitable material, which transfers the heat from the solar collection system 150 and the associated radiant energy to the oil shale strata 110. It can be appreciated that the heat transport material 125 can be selected based on the heat transfer properties of the material 125, including desired temperature range and/or viscosity of the heat transport material 125.

In accordance with an exemplary embodiment, a circulating pump system 196 can be used to pump (or force) the heat transport material 125 through an output pipe or tube 198 to a desired and/or required strata zone 118. It can be appreciated that the circulating pump system 196 can be located at any desired depth within the well casing 120. In a preferred embodiment, the depth and/or location of the circulating pump system 196 is preferably at a depth or location within the well casing 120, which optimizes the radiant energy produced by the solar collection system 150, the heat transfer properties of the heat transport material, and the depth of the oil shale strata 110. The system 100 can also include a subterranean heat source (not shown), which can add additional heat to the radiant energy from the solar collection system 150 and/or the heat transport material 125.

The system 100 as shown in FIG. 2, includes a well hole or drill shaft 102 having a well casing 120, which includes a leak-tight shaft liner 122, and a gas evacuating system 140 to remove gases from an inner portion or interior 124 of the well casing 120. The system 100 also includes a solar collection system 150 for collecting and directing a collimated light beam 160 of radiant energy to a thermal conductive body 136 located within the well casing 120. The thermal conductive body 136 is preferably located within the well casing 120 at a location or depth generally above the oil shale strata 110. The location or depth of the thermal conductive body 136 within the well casing 120 is preferably a function of the radiant energy produced by the solar collection system 150, the heat transfer properties of the heat transport material 125, and the depth of the oil shale strata 110.

In accordance with an exemplary embodiment, the thermal conductive body 136 transfers or conducts the radiant energy from the solar collection system 150 to the heat transport material 125. The heat or radiant energy from the solar light beam 160 is then conveyed down-hole by the heat transport material 125 via convection and/or with the assistance of the circulating pump system 196 and/or piping system 198. It can be appreciated that the evacuated, optical portion of the shaft or well casing 120 prevents the radiant energy or heat from escaping away from the oil shale strata 110 (i.e., target area), and further an optimal level can be set for passive convection of the heat transport material 125. In addition, the heat transport material 125 supports the delivery of the radiant energy to the oil shale strata 110 in directional drilling and non-linear well holes or well casings 120.

It can be appreciated, that since the target oil shale strata 110 is generally horizontal in nature, the system 100 can utilize a plurality of spaced-apart well holes to provide long term heating to the oil shale strata 110. Alternatively, the system 100 can implement a directional drilling or slant drilling system by drilling non-vertical wells from one or more well holes to increase the target area and allow the radiant energy to reach the generally horizontal oil shale strata 110. In accordance with an exemplary embodiment, a directional drilling system can be utilized to provide a single well hole or well casing having a plurality of fingers or well bores (i.e., star formation) extending essentially horizontally outward from the single well hole or well casing 120 to allow the radiant energy generated by the system 100 to heat the oil shale strata 110 to the desired temperature. In accordance with an exemplary embodiment, the directional drilling system utilizes a heat transport material 125 to allow for the non-linear conditions in directional drilling or slant drilling systems.

FIG. 3 is a cross-sectional view of a system 200 of in-situ oil recovery utilizing a non-imaging optical system in accordance with another exemplary embodiment. As shown in FIG. 3, the system 200 includes a solar collection area 202 having a steerable reflector system 206, and an oil drilling area 204 having a fixed or stationary reflector system 208, which are used to concentrate solar energy radiating from the sun (not shown). The steerable reflector system 206 is preferably positioned within a solar collection area 202, which can optimize solar conditions, including optimum sight lines and collection abilities. In accordance with an exemplary embodiment, the solar collection area 202 is preferably adjacent to the oil drilling area 204.

The system 200 is preferably comprised of a non-imaging optical system, which optimizes the transfer of light radiation or radiant energy between the sun (not shown) and the oil shale strata 210. As shown in FIG. 3, the steerable reflector system 206 includes a plurality of reflective mirrors 220, 230, 240 having a corresponding reflective surface 222, 232, 242. In accordance with an exemplary embodiment, the first reflective mirror 220, having a heliostat associated therewith, has a curved reflective surface 222, which is preferably concave, and more preferably spherical or parabolic in shape. A second reflective mirror 230 having a convex reflective surface 232 receives the beams of light from the first reflective surface 222. A third reflective mirror 240 having a flat or planar reflective surface 242 receives the beams of light from the second reflective mirror 230 and directs the plurality of solar beams and radiant energy to the fixed or stationary reflector 208.

The fixed or stationary reflector 208 includes a first reflective mirror 250 having a concaved reflective surface 252, which is preferably spherical or parabolic in shape. A second reflective mirror 260 having a convex reflective surface 262 receives the beams of light from the first reflective surface 252. A third reflective mirror 270 having a flat or planar reflective surface 272 receives the beams of light from the second reflective mirror 260 and directs the plurality of solar beams to the well casing 214 and oil shale strata 210 and oil shale 212 located below. It can be appreciated that unlike traditional imaging optics, the non-imaging optical system 200 as shown in FIG. 3 does not attempt to form an image or concentration of the radiant energy, but instead optimizes the radiative transfer from the source (i.e., sun) to the target (i.e. oil shale strata 210) by directing a plurality of light beams having radiant energy through the well casing 214 to the strata 210 of oil shale 212.

It can be appreciated that in accordance with a further embodiment, each of the well casings 214 can be associated with one or more non-imaging optical systems 200, and wherein each system 200 includes a plurality of solar collection areas 202, each having a steerable reflector system 206 and an oil drilling area 204 having at least one fixed or stationary reflector system 208

FIG. 4 is a cross-sectional view of a solar collection system 300 in accordance with an exemplary embodiment, wherein the system 300 is a non-optical imaging system. As shown in FIG. 4, the system 300 includes a first reflective mirror 310 having a heliostat (not shown), a second reflective mirror 320 and a third reflective mirror 330. In accordance with an exemplary embodiment, the first reflective mirror 310 has a concaved reflective surface 312, which is preferably spherical or parabolic in shape and an outer portion 314. The concaved reflective portion 312 includes a reflective surface 316, which receives (or collects) a source of solar heat preferably in the form of a plurality of beams of light, light rays, solar energy, solar flux or radiant energy 340 from the sun. The reflective surface 316 of the first reflective mirror 310 then directs (or distributes) the beams of light 340 to the second reflective mirror 320.

The second reflective mirror 320 having a convex reflective portion 322 receives the beams of light 350 from the first reflective portion 312 and directs the beams of light to a third reflective mirror 330. The second reflective mirror 320 also includes an outer portion 334 and a reflective surface 326. The third reflective mirror 330 has a flat or planar reflective surface portion 332, which receives the beams of light from the second reflective mirror 320 and directs the plurality of solar beams of radiant energy 370 to the well casing (not shown) and to the strata of oil shale (not shown) located below.

FIG. 5 is a cross-sectional view of the second and third reflective mirrors 420, 430 of a solar collection system 400 in accordance with another exemplary embodiment. As shown in FIG. 5, a plurality of light beams 450 are reflected off a first reflective or parabolic mirror (not shown) and which is received by the second reflective mirror 420. In accordance with an exemplary embodiment, the second reflective mirror 420 is a non-imaging faceted mirror having a reflective surface 422 comprised of a plurality of facets 426. It can be appreciated that in accordance with an exemplary embodiment, the plurality of facets 426 reduces the divergence within the system 400.

The third reflective mirror 430 is preferably a flat or planar mirror, which receives the plurality of light beams 460 from the non-imaging faceted mirror 420. The third reflective mirror 420 collects and distributes the light beams 470 in a light path 480.

In accordance with an exemplary embodiment, the systems 300, 400 as shown in FIGS. 4 and 5 can include a first reflective mirror (M1) having a 15 foot diameter and a f1 of 7.5 feet (with inherent divergence of approximately 10 mrads), a second reflective mirror (M2) having a 12 inch diameter and a f2 of approximately 0.45 feet and spaced from the first reflective mirror at a distance of approximately 7 feet, and third reflective mirror (M3). In accordance with an exemplary embodiment, the second reflective mirror is a non-imaging faceted mirror having a 12 inch diameter with approximately 400 facets, which can reduce the divergence to 0.5 mrad with focus at 1000 feet. With the above-mentioned 12 inch faceted mirror and a third planar mirror, a light path 480 can be produced having a ½ inch width per facet (0.5 mrad divergence after the second reflective mirror 420) for a target (i.e., strata of oil shale) at 1000 feet, the light path having a width of ½ of an inch preferably fits within a well casing having a diameter of at least 6.5 inches (D1=0.5+1000×12×1/2,000=6.5 inches).

In accordance with another exemplary embodiment, it can be appreciated that with the non-imaging optical systems 200, 300, 400 can employ a variety of technologies alone or in combination, for example, compound parabolic concentrators as shown in FIGS. 3-5, adaptive mirror arrays with Fresnel lens (i.e., computer controlled mirrors that focus the mirrors on a common target), parabolic trough generators, hemispherical solar concentrators, and/or Fresnel lenses or prisms.

It can be appreciated that the system and methods 100, 200, 300, 400 as described herein can be extended or applied to other mineral operations, which benefit from a subterranean heat source.

It will be understood that the foregoing description is of the preferred embodiments, and is, therefore, merely representative of the system and method. It can be appreciated that many variations and modifications of the different embodiments in light of the above teachings will be readily apparent to those skilled in the art. Accordingly, the exemplary embodiments, as well as alternative embodiments, may be made without departing from the spirit and scope of the articles and methods as set forth in the attached claims. 

1. A system for in-situ oil shale recovery comprising: a well casing having a leak-tight shaft liner; a gas evacuating system for removing gases from the well casing; and a solar collection system for directing radiant energy through the well casing to a strata of oil shale.
 2. The system of claim 1, wherein the solar collection system comprises at least one concentrator, at least one collimator, and at least one aiming mirror.
 3. The system of claim 2, further comprising a heliostat.
 4. The system of claim 1, wherein the solar collection system is a non-imaging optical system.
 5. The system of claim 4, wherein the non-imaging optical system includes a plurality of non-imaging reflective mirrors.
 6. The system of claim 1, wherein the well casing includes a transparent top window and an opaque bottom plug.
 7. The system of claim 6, further comprising a bottom window, the bottom window positioned within the well casing at or slightly above an upper portion of the strata of oil shale.
 8. The system of claim 1, wherein a lower section of the shaft liner adjacent to a target strata of oil shale includes a surface treatment, which absorbs heat from the radiant energy.
 9. The system of claim 8, wherein the surface treatment is a heat resistant stainless steel fiber.
 10. The system of claim 1, wherein an upper portion of the liner includes a reflective surface treatment.
 11. The system of claim 2, wherein the at least one concentrator further includes at least one beam shaping lens.
 12. The system of claim 1, further comprising a flush tube, which is adapted to remove gaseous materials from the well casing. 13 The system of claim 1, further comprising a heat transport material having a negative thermal expansion coefficient so that heat from the radiant energy is conveyed down-hole by convection.
 14. The system of claim 13, wherein the heat transport material is a liquid salt.
 15. A light tube comprising: one or more solar collectors for collecting and directing radiant energy; an evacuated well casing; a liner within the evacuated well casing, the liner having an internal surface treatment to minimize thermal absorption in an upper section of the well casing; one or more transparent, gas tight windows positioned within the well casing; and an absorber surface treatment on a lower section of the well casing, the lower section of the well casing being adjacent to a target rock strata, which produces an in-situ oil recovery by absorbing the radiant energy and effectively transmitting the resultant heat to the target rock strata.
 16. The light tube of claim 15, wherein the one or more solar collectors are non-imaging reflective mirrors.
 17. The light tube of claim 16, wherein the non-imaging reflective mirrors comprise a pair of non-imaging reflective mirror systems having a concave reflective mirror, a convex reflective mirror, and a planar reflective mirror.
 18. A method of in-situ oil shale recovery comprising: evacuating a well casing; lining an upper section of the well casing with an internal surface treatment to minimize thermal absorption; applying a surface treatment on a lower section of the well casing adjacent to a target strata of oil shale, the surface treatment adapted to absorb radiant energy; and producing in-situ oil recovery by transmitting the radiant energy to the target strata of oil shale.
 19. The method of claim 18, further comprising collecting and directing the radiant energy by collimating a plurality of solar beams into a single solar beam.
 20. The method of claim 18, further comprising collecting and directing the radiant energy using a plurality of non-imaging reflective mirrors. 